An English-born interior designer, now based in Los Angeles, Dunham has no fear when it comes to bold patterns, splashy textiles, and eclectic mixes of vintage and modern. It’s one reason his eponymous textile line and Hollywood at Home retail store attract everyone from high-profile home decorators (even Ellen DeGeneres) to modest DiYers looking to make a splash. Here, his pointers for the print-shy.

What’s the biggest mistake people make when trying to be bold? They mess up scale. They only choose little patterns, so it has the same boring rhythm. Or they mix a stripe with something crazier in the same room. You don’t want two people talking too loudly on the same sofa — they need to converse.

After your travels, what’s California brought to the mix? The impact of America in my life can’t be understated. It’s about practicality, a casual lifestyle, and comfort.

Most people tend to go neutral. How do they turn it up a notch? Start with buying cushions, pillows, or a chair. People will say they don’t need a window treatment, but one pair of great curtains in someone’s house transforms it.

Why does wallpaper freak out folks? It shouldn’t. It gives you the biggest bang for your buck; there’s nothing else you can do to your room and get more of an effect. I use it for texture—raffia, woven herringbone. But when it’s in every room, then the music’s the same beat. I’m a strong advocate for color, but I will only do one room like that.

So that’s the secret to the “wow” factor? You can’t “wow” 20 times in one house—do it once or twice.

Anything you can’t stand? I’m good with denial, but I hate when people do an accent wall. They think it looks good and has less of an impact, but it actually creates more contrast. Plus, it looks like you didn’t have enough of a budget to do the whole room. Save up for when you can.